Article R*49-30 of the French Code of Criminal Procedure
The parties have a period of one month from the decision to refer the question of constitutionality to the Cour de cassation to make known any observations they may have before the Court. They are signed by a lawyer at the Conseil d’Etat and the Cour de cassation, in accordance with the rules set out in article 585, except where they are submitted by the convicted person, the civil party…